The invention concerns a combinatorial method for the generation of new split-protein sensors, and its application towards the (beta/alpha)8-barrel enzyme N-(5'-phosphoribosyl)-anthranilate isomerase Trp1p from Saccharomyces cerevisiae is demonstrated. The generated split-Trp protein sensors allow for the detection of protein-protein interactions in the cytosol as well as the membrane by enabling trp1 cells to grow on medium lacking tryptophan. This powerful selection thus complements the repertoire of the currently used split-protein sensors and provides a new tool for high-throughput interaction screening.